Solenoid airless spray gun



Oct. 19, 1965 Filed June 19, 1963 E. H. COCKS SOLENOID AIRLESS SPRAY GUN2 Sheets-Sheet 1 INVENTOR K: x-ncoms,

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ATTORNEYS Oct. 19, 1965 E. H. cocKs SOLENOID AIRLESS SPRAY GUN 2Sheets-Sheet 2 Filed June 19, 1963 INVENTOR ma Accaovs,

BY flaw & @u'amwyw ATTORNEY5 United States Patent 3,212,715 SOLENOIDAIRLESS SPRAY GUN Eric H. Cocks, 21 Crane Ave., West Caldwell, NJ. FiledJune 19, 1963, Ser. No. 289,030 1 Claim. (Cl. 239-125) This inventionrelates to a spray gun, and more particularly to an airless spray gunused to atomize fluids by hydraulic pressure without the use of acompressed air supply.

In the field of automatic spray painting it is desirable that the sprayguns be trouble free and repetitive in action, since in many instancesthere are not attendants to make corrections for erratic operation. Anelectrically operated spray apparatus is ideally suited for automaticoperation, particularly when the apparatus is at a location remote fromthe point of control. The use of a solenoid control for operating thevalve mechanism of a spray gun has been suggested in the past, and thisarrangement is adapted readily for automatic operation. However, withall of the known devices, the problems of erratic plunger operationbecause of improper cleaning and excessive wear have remained adeterrent for the production of an apparatus having reliable operations.The principal reason for this is that the structure of the gun does notlend itself readily to a complete cleaning or flushing to remove oldfluids from the operating mechanism.

It is an object of this invention to provide a spray gun for highpressure airless spraying which will be simple in construction and rapidand reliable in operation.

Another object of the invention is to provide a spray gun which is notsubject to leakage around seals under pressure.

Another object of the invention is to provide a spray gun which iscleaned easily both internally and externally.

A further object of the invention is to provide an electrically operatedspray gun with means for quickly and reliably connecting the operatingsolenoid to an external power supply.

A still further object of the invention is to provide an electricallyoperated spray gun suitable for hand operation.

In accordance with the invention these objects are realized in anapparatus comprising a cylinder having end closure members forming ahollow housing. The end closure members are held in position by atubular member which is threaded at both ends and mounted concentricallywith said cylinder. One end of the tubular member is threaded into thefirst closure member to define a fluid chamber. The first closure memberalso has an aperture with a resilient valve seat insert communicatingwith the fluid chamber.

The tubular member has an internal fluid passageway in alignment withthe fluid chamber. The pasageway is enlarged at the end nearest thefirst closure member to the same diameter as the fluid chamber. A valveplunger having an internal fluid passageway is slidably positionedwithin the enlarged end of the tubular member. One end of the plungerhas a tapered tip which serves as the closure for the resilient valveseat insert. A solenoid is positioned within the housing around thetubular member to attract the valve plunger away from the resilient seatwhen the solenoid is energized. The plunger has a spring member withinthe fluid passageway to bias the plunger against the resilient valveseat when the solenoid is not energized.

The foregoing and other objects, features and advan-" tages of theinvention will be apparent from the following more particulardescription of two embodiments of the invention as illustrated in theaccompanying drawings in which:

FIG. 1 is a cross-sectional view in elevation of a first See embodimentof the invention adapted for stationary installation in an automaticsystem;

FIG. 2 is a cross-sectional view in elevation of a second embodiment ofthe invention adapted for hand-held use; and

FIGURE 3 is a perspective view of the valve plunger and biasing spring.

The invention will be understood more readily by making reference toFIG. 1 of the drawings which is a crosssectional view of an assembledgun construction in accordance with the features of the invention. Thegun comprises a cylinder member 1 having end closure members 3 and 5.The end closure members 3 and 5 are held in assembled relationshipagainst cylinder 1 by means of a tubular member 7 which has externalthreads on each end and an internal fluid passageway 17. One end of thetubular member 7 is threaded into the end closure 3 to form a fluidchamber indicated generally by the numeral 9. An appropriate fluid sealsuch as gasket 11 is provided between tubular member 7 and end closure3.

Fluid chamber 9 has a valve plunger 13 slidably mounted therein. Thevalve plunger 13 has an internal fluid passageway 15 which is insubstantial alignment with the internal fluid passageway 17 of tubularmember 7. The fluid chamber 9 has an aperture 19 in which is mounted aresilient valve insert 21. The valve plunger 13 is provided with atapered tip 23 which provides the closure for the resilient valve insert21. Tapered tip 23 is normally biased against resilient valve insert 21to close completely aperture 19 by means of a spring 25 located withinthe internal passageway 15 of valve plunger 13.

A solenoid 27 is mounted within hollow portion 29 of the housingconcentrically with cylinder member 1 and tubular member 7. Anelectrical connecting cable 31 is connected to soleoid 27 and passesthrough aperture 23 in end closure 5 to an appropriate external sourceof electrical power. Easy access is provided for the electrical assemblysince nuts 35 and 37 provide the only retaining means for end closure 5,cylinder member 1, solenoid 27 and solenoid retaining plate 39. Also,since the hollow portion 29 provides ample internal space, theelectrical connecting cable 31 may be connected to solenoid 27 such thatall connections are located within the housing itself.

Fluid chamber 9 may be provided with an additional aperture 41 whichserves as a by-pass connection for a fluid supply line illustrateddiagrammatically by numeral 43. When a bypass line is utilized asuitable by-pass control arrangement shown generally at 45 and a supplypump arrangement 47 are connected in closed circuit with the spray gunso that a continuous circulation of fluid can be maintained when the gunis not operating. This prevents the settling of any sediment in thefluid and clogging of the apparatus.

The gun shown in FIG. 1 is designed for an automatic installation to beoperated at a remote location. The gun is held in position to sprayarticles, which may be moving past the gun on an assembly conveyor, bymeans of mounting post 49 which is threaded into end closure 3.Appropriate positioning linkages (not shown) may be connected tomounting post 49 to allow the positioning of the gun in any desiredmanner.

In operation the supply pump 47 supplies fluid under pressure to the gunthrough internal fluid passageway 17 of tubular member 7. The operatingpressure of the system may be 3000 psi. which is very high compared toconventional systems. The valve plunger 13 is biased by spring 25 sothat tapered tip 23 engages the resilient valve insert seat 21 to closeoil aperture 19. When it is desired to begin the spring operation,solenoid 27 is energized from a remote location through electricalconnecting cable 31. The energizing of solenoid 27 causes valve plunger13 to be attracted away from aperture 19, and the tapered tip 23 isremoved from engagement with the resilient valve insert 21, therebyopening aperture 19. The gun is designed so that a very small movementof valve plunger 13 in either direction is all that is required to openand close aperture 19. The use of the tapered tip 23 in combination withresilient valve seat insert 21 provides a positive sealing action. Thispositive sealing action, together with the very short plunger travel,enables rapid actuation of the gun and insures positive shut off.

The valve action of the present spray gun has op-' erational advantagesover conventional valve actions because of the short, but rapid, plungertravel. A typical airless spray gun has a relatively slower movingvalve. In high pressure operation the slower moving valve of the priorart would permit an initial escape of fluid before it is fully open. Thereverse action would occur when closing. Any change in size in theorifice results in a change of pressure on the fluid, and even though itis of very short duration, it is reflected in the spray pattern by achange in the degree of atomization. This produces a spattering efiectat the start and finish of the spray. The apparatus of the presentinvention is not subject to these undesirable features.

' When solenoid 27 is operated and aperture 1.9 is opened, the fluidunder pressure from supply pump 47 is forced in a straight line throughthe gun assembly and out nozzle structure 51, which is of conventionaldesign. The high pressure flow of fluid through nozzle structure 51causes atomization of the fluid and the formation of a suitable spraypattern in accordance with features which are well known in the art.When valve plunger 13 is closed upon de-energizing the solenoid, by-passcontrol 45 is opened to allow circulation of the fluid through thesystem and maintain the apparatus in condition for immediate operation.Since the fluid passes through solenoid 27 at all times, the heatgenerated by current through solenoid 27 is quickly dissipated.

When the apparatus is to be cleaned, a cleaning fluid is substituted forthe working fluid normally supplied, and the pump 47 forces the cleaningfluid through the system. Because of the straight line arrangement offluid flow, there is no opportunity for fluid to collect inoutof-the-way recesses present in conventional gun arrangements.Therefore, the spring 25, plunger 13 and all passageways are cleared ofany residue by the fl-ow of cleaning therethroug'h. This marks asubstantial improvement over conventional guns in which the valveplunger and biasing spring are normally located out of the line of flowof fluid, and residue collects readily to impair the spring and valveaction.

A second embodiment of the invention is shown in FIG. 2 wherecorresponding-parts have been given the same numerals as those appearingin FIG. 1. This gun is designed for hand-held operation. The end closuremembers 3' and are similar to end closure members 3 and 5 of FIG. 1,except that the apertures for by-pass control, mounting posts andelectrical connecting cable are not required. The cylinder member 1'forming the body of the gun apparatus has an integral handle member 53which is hollow and contains a battery 55. A pair of contacts 57, 59 areoperated by a finger-actuated plunger 61, which is biased by spring 63.Access to the battery 55 for replacement purposes may be gained by meansof a removable plate (not shown).

The operation of the gun of FIG. 2 is identical to the operation of theembodiment shown in FIG. 1 except that the solenoid is actuated by theoperator holding the gun, instead of at a remote location. In this caseit is 4! not necessary to provide a by-pass fluid arrangement, sincecontinuous operation over long periods of time is not contemplated in ahand apparatus.

From the foregoing description it will be appreciated that the presentinvention has provided a spray gun for high pressure spraying which willbe simple and fast in operation, will have a minimum number of parts andwill be cleaned easily both internally and externally. The housingstructure for the electrical solenoid provides a means of easily andreliably connecting the solenoid to a power supply Without hazardous andunsightly external electrical connections. The fast action and positivefeeding of the valve enable this device to be used in applications whereprecise control is required.

While the invention has been shown and described with particularreference to preferred embodiments, it will be understood by thoseskilled in the art that various changes in form and details may be madewithout departing from the spirit and scope of the invention.

What is claimed is:

An airless spray gun for fluids comprising a cylinder having first andsecond end closure members forming a hollow housing, a tubular memberhaving a first internal fluid passageway mounted concentrically withsaid cylinder to define a hollow annular space within said cylinder, oneend of said tubular member being threaded into said first closure memberto define a fluid chamber and the other end being adapted to beconnected to a source of fluid supply, a first aperture within saidfluid within said second closure member for making electricalconnections to said solenoid solely within said cylinder, and a thirdfluid passageway communicating with said fluid chamber to provide abypass path for said fluid to insure continuous fluid circulation whensaid gun is not in operation, said second internal fluid passageway insaid valve plunger being in substantial alignment with said firstaperture and said first internal fluid passageway in said tubularmember, whereby the flow of fluid through said gun is substantially in astraight line passing through said first and second fluid passagewaysand over said spring member to insure rapid and thorough cleaning of themoving plunger and spring member.

References Cited by the Examiner UNITED STATES PATENTS 1,504,773 8/24Marston 239585 1,664,616 4/28 French 239585 1,792,929 2/ 31 Remey239-585 2,305,290 12/42 Fuscaldo 239- 2,540,357 2/51 Stanley 2393322,743,137 4/56 Wilson 239- 2,999,646 9/61 Wagner 239--526 3,067,95412/62 Hooper 239-582 FOREIGN PATENTS 217,249 9/ 61 Austria.

672,5 73 3 39 Germany.

852,481 10/60 Great Britain.

M. HENSON WOOD, JR., Primary Examiner.

EVERETT W. KIRBY, Examiner,

